A deserted street inside the contaminated exclusion zone around the crippled Fukushima Dai-ichi nuclear power station, on Nov. 12, 2011. Experts say health effects of radiation exposure likely won't be detectable and a bigger problem is the mental health issues resulting from the trauma of the tsunami.

David GuttenfelderAFP/Getty Images

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Originally published on March 12, 2012 11:09 am

One year ago this Sunday, a 9.0 magnitude earthquake off Japan triggered a tsunami that killed 20,000 people. It also triggered multiple meltdowns at the Fukushima Dai-ichi nuclear power station, one of the worst nuclear disasters in history.

But health effects from radiation turn out to be minor compared with the other issues the people of Fukushima prefecture now face.

That may come as a surprise. We all watched frightening TV images, and clouds of radioactive steam and gas did erupt from the plant. That material did sometimes move over the countryside and into populated areas, so it looked like a horrible disaster.

But in the case of radiation, the dose matters. It's true, there is no bright line that separates a safe dose of radiation from a dangerous dose, but at some point, a dose is so small that any potential health risk is simply too small to measure.

"Surprisingly, there have been no health effects that have been demonstrated among the Japanese people or among the workers," says John Boice, a cancer epidemiologist at Vanderbilt University.

To be sure, "there was radiation released. It was about a tenth of what was released from Chernobyl," he says. "But most of the releases were blown off to the Pacific Ocean. The winds were blowing to the sea and not to populated areas."

One big cloud did blow inland, up toward the northwest. But most of the 170,000 residents in the area were quickly evacuated. Boice says that helped limit dangerous doses. So did other quick actions by the Japanese government.

"They prohibited the release of any food that had had increased levels of radiation in them," he says. "So there wasn't milk out there in the public supply. There wasn't any fish that had levels that were increased."

And that's a huge difference from the aftermath of Chernobyl. In 1986, the Soviets let people eat contaminated food and drink contaminated milk, activity that led to many cancers. In Japan, Boice says the only people with significantly elevated doses are the nuclear workers. And as a result, a few workers are at slightly higher risk for cancer.

Psychological Health Effects

Robert Gale, a bone-marrow-transplant expert who treated workers after Chernobyl, spent half of the past year in Japan talking to some of the thousands of workers called in for the nuclear cleanup.

"Most of these workers are not nuclear workers," Gale says. "They are common workers that [for example] were upholstering couches in Osaka and now they're cleaning up a nuclear reactor."

They work until they reach the occupational radiation limit of 50 millisieverts in a year, then they go home. But they don't know what their risk really entails. So Gale has been meeting with them to explain.

"Usually, when they're discussing these issues we're in an izakaya, a sort of Japanese bar," he says. "While they're discussing their concerns about radiation with me, they can go through a pack of cigarettes. If you smoke a pack of cigarettes a day for a year, you're getting an internal radiation dose of about 30 millisieverts."

That's more than half the dose they got through occupational exposure. But cigarette smoke is also filled with cancer-causing chemicals, so smoking is a far bigger risk to their health.

But the issue isn't just physical health — it's the worries that come with radiation. Evelyn Bromet, a psychiatry researcher at SUNY Stony Brook, says this anxiety sets in after big nuclear accidents.

"The central public health issue often becomes health-related anxiety, concerns about the future, about the future health of the children," Bromet says. "So that's what happened in Japan, just as it happened after Chernobyl and after Three Mile Island."

But it's worse in Japan because the public is also suffering from the trauma of the tsunami, of evacuation and of losing livelihoods, because people are reluctant to buy produce from Fukushima. And Bromet says physicians in Japan don't generally treat mental health issues.

"So I think it's not going to be very easy to set up intervention programs in the same way it would in countries like Holland, for example, where there's much more integrated mental and physical health care."

Bromet says it will be essential to deal with both physical health and mental health in the years to come.

Copyright 2014 NPR. To see more, visit http://www.npr.org/.

Transcript

STEVE INSKEEP, HOST:

Japan's nuclear disaster was awful. But it turns out the emotions triggered by the crisis were worse than the actual radiation.

NPR's Richard Harris reports on the cost of fear.

RICHARD HARRIS, BYLINE: There is no bright line that separates a safe dose of radiation from a dangerous dose. But at some point, a dose is so small, any potential health risk is too small to measure. That's the case for the radiation clouds that settled on northern Japan last March.

John Boice is a radiation expert at Vanderbilt University.

JOHN BOICE: Surprisingly, there have been no health effects that have been demonstrated among the Japanese people or among the workers.

HARRIS: That's a surprise, because we all watched frightening TV images, and clouds of radioactive steam did erupt from the plant, and that material did sometimes move over to countryside and into populated areas. So it looked like a horrible disaster.

BOICE: Now, that's exactly right. There was radiation released. But most of the releases were blown off to the Pacific Ocean. The winds were blowing to the sea and not to populated areas.

HARRIS: Most people were quickly evacuated. About 170,000 people live close to the plant. Boice says that helped limit dangerous doses. So did other quick actions by the Japanese government.

BOICE: They prohibited the release of any food that had had increased levels of radiation in them. So there wasn't milk out there in the public supply. There wasn't fish that was - had any levels that were increased.

HARRIS: And that's a huge difference from the aftermath of Chernobyl. The Soviets in 1986 let people eat contaminated food and drink contaminated milk. That led to many cancers. Robert Gale treated workers after Chernobyl. He also spent half the last year in Japan. He's been talking to some of the thousands of workers called in for the nuclear cleanup.

ROBERT GALE: Most of these workers are not nuclear workers. They are common workers that, you know, were upholstering couches in, you know, in Osaka, and now they're cleaning up a nuclear reactor.

HARRIS: They work until they reach the occupational radiation limit of 50 millisieverts in a year, then they go home. But they don't know what their risk really entails, so Dr. Gale meets with them to explain.

GALE: Usually, when they're discussing these issues we're in an izakaya, you know, a sort of Japanese bar. While they're discussing their concerns about radiation with me, they are - you know, they can go through a pack of cigarettes. And, you know, if you smoke a pack of cigarettes a day for a year, you're getting an internal radiation dose of about 30 millisieverts.

HARRIS: Thirty for smoking one year, versus 50 by working at the ruined plant. Plus, cigarettes are filled with cancer-causing chemicals, so smoking is a far bigger risk to their health. But the issue isn't just physical health - it's the worries that come with radiation.

EVELYN BROMET: Concerns about the future, about the future health of the children.

HARRIS: Evelyn Bromet is a psychiatry researcher at SUNY Stony Brook.

BROMET: So that's what happened in Japan, just as it happened after Chernobyl and after Three Mile Island.

HARRIS: Only in Japan, the public is also suffering from the trauma of the tsunami. They're suffering from the trauma of evacuation, the trauma of losing livelihoods because people won't buy produce from Fukushima. And Bromet says physicians in Japan generally don't treat mental health issues.

BROMET: So I think it's not going to be very easy to set up intervention programs in the same way it would be in a country where there - like Holland, for example, where there's much more integrated mental and physical health care.

HARRIS: Bromet says it will be essential to deal with both physical health and mental health in the years to come. Richard Harris, NPR News.

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